Nagaraja is a Tamil word from naga (snake) and raja (king) meaning "king of snakes". It is applied to three main deities, (Sheshanaga), Takshaka, and Vasuki. Ananda, Vasuki and Takshaka are brothers, children of Kashyapa and Kadru, who are the parents of all snakes.
Shesha, the eldest brother, was a devotee of Vishnu, and represents the friendly aspect of snakes, as they save food from rodents. Lord Vishnu is always on continuous meditation (Yoganidra) with Ananda forming a bed for him, and this posture is called Ananda-Sayana.
A temple devoted to Nagaraja exists in Poojappura of Thiruvananthapuram District in Kerala, India. It is known as Poojappura nagarukavu Temple. The uniqueness of this temple is that here the family of the Nagaraja including Nagaramma, Queen of Naga and Nagakanya, Princess of the Naga kingdom is placed inside a single temple.